Canada’s stillbirth rate appears to be rising not because more fetuses are dying spontaneously but because more pregnancies are being terminated due to serious birth defects, researchers are reporting.

After decades of decline, rates of stillbirth — defined as the death of a fetus after 20 weeks’ gestation or when it weighs more than 500 grams — have increased in recent years in several countries, including in Canada, researchers wrote in this week’s issue of the Canadian Medical Association Journal.

The question is, why?

“The prevention of stillbirth through early delivery of the compromised fetus is considered the cornerstone of modern obstetrics,” the researchers wrote, and any sudden change in the trend is worrying. Some have speculated the increase in stillbirths could be due to more older mothers, or multiple births from fertility treatments.

But another explanation is pregnancy terminations for severe birth defects — therapeutic abortions “which can result in a fetal death that satisfies the current definition of a stillbirth,” the authors wrote.

“Historically, stillbirths that occur later on in pregnancy usually occur because of some pregnancy complication, meaning there is a problem with (the mother’s) health or a problem with fetal health,” said author Dr. K.S. Joseph, a professor in the department of obstetrics and gynecology at the University of British Columbia, as well as at the university’s School of Population and Public Health. Stillbirth rates had been declining because of improvements in detecting and managing problems during pregnancy. “If the rate of stillbirth is high, that’s a problem.”

In an attempt to explain the “unexpected phenomenon,” Joseph and his coauthors looked at data on all stillbirths of 20 weeks’ gestation or older in the province of B.C. from 2000 to 2010.

Overall, a total of 461,083 live births and 3,991 stillbirths were registered during the 10-year study period in the database of Perinatal Services BC.

The rate of recorded stillbirths increased 31 per cent, from 8.08 per 1,000 total births, to 10.55 per 1,000 births by 2010.

Next they looked at stillbirths according to whether they were spontaneous or resulted from a termination.

Spontaneous stillbirth rates have not increased. Instead, “what we found was that the increase in stillbirths seems to be because we have more acceptance and uptake of prenatal diagnosis and pregnancy termination for congenital anomalies,” Joseph said.

Fetal screening starting at around 18 weeks’ gestation can detect major chromosomal abnormalities as well as serious malformations of the brain and spine, such as anencephaly, a condition where most of the brain is missing, and complex heart defects. With anencephaly, “that would be a very straightforward decision to terminate the pregnancy, because that’s incompatible with survival,” Joseph said. “The baby may be born alive, but it cannot live because it doesn’t have a brain.”

If the pregnancy isn’t terminated, the baby can die in the womb. But the other possibility is that the baby is born alive, and then dies.

Today, when fetal screening detects a lethal or serious defect, “the woman is offered the option of termination,” Joseph said.

But if termination occurs after 20 weeks, it gets classified as a stillbirth. “So this is adding to our stillbirth rate.”

The researchers found that the overall rate of pregnancy terminations, whether resulting in a stillbirth or live birth, increased from 2.4 per 1,000 total births to 5.7 per 1,000 births over the study period.

Different medical procedures are used for pregnancy termination in these cases. “Some involve initiating labour, say at 20 or 22 weeks, and the procedure ends with delivery of the baby,” Joseph said.

“Occasionally, and even despite the birth defect, such babies can be born alive.”

The definition of a live birth in Canada states that a baby is born alive if there are any signs of life, he said, “such as a heart beat, movement of the voluntary muscles or pulsation of the umbilical cord after the baby has been delivered from the mother.

“As you can imagine, such situations are extremely challenging for parents and health-care providers and babies receive palliative care for the short time they continue to live.”

The increase in pregnancy terminations was associated with a drop in the prevalence of congenital abnormalities among live-born infants, the researchers said.

Other factors may be at play: Fewer women are smoking during pregnancy and rates of neural tube defects — devastating malformations of the brain and spine — have fallen dramatically in Canada since the introduction of folic-acid fortified foods in 1998.

But prenatal diagnosis is also clearly having an impact, Joseph said, “and that, too, is good, because it offers parents a choice. With some of these lethal malformations, the baby is born alive and then can live for days and then die.”

The researchers also found that bureaucratic rules from the past are placing undue stress on couples grieving the loss of a much-wanted pregnancy. In most provinces, parents, and not the doctor or hospital, have to complete a stillbirth registration, a process that can place an “undue psychological burden on parents,” the researchers wrote in the CMAJ.

One solution “would have the onus for stillbirth registration (and disposal of the fetal remains) placed on the health care provider and health care system and not on the distressed parents,” they said.

“The parents have to make the arrangements with a funeral home, it’s essentially their responsibility,” Joseph said.

“Stillbirths affect different people differently. Some want to be very involved. But others are so grief-stricken they find it an enormous challenge and emotionally taxing to have to do these things,” he said.

In cases where parents are distraught, “we want the rules changed so that the stillbirth registration process can be taken over by the hospital personnel.”